Best glue for PLA?

[Alex Lau]

I've tried zap-a-gap and other types of cynoactlayte (Sp?) and they don't seem to work to my satisfaction. Maybe the setting time is too long or something, but my models always seem to fall apart. Soldering the plastic together works well but it leaves messy seams and isn't good for interior pieces.

What glues does everyone use for their PLA models? A list of brands would be helpful (especially anyone living in NYC).

[Matt Larson]

Alex,

I had good luck using Hot Glue with PLA.  The hot glue and PLA seem to fuse together well.

Another similar question - has anyone been able to waterproof a PLA object?  

I tried to use a heat-gun to melt the surface smooth, but this does not work well with PLA.  Instead, the whole object will warm together and become flexible before the surface melts.  

So, I am guessing some sort of a lacquer might be needed.

 -Matt

On Wed, Jan 23, 2013 at 12:49 PM, Alex Lau <alex...@hublished.com> wrote:

I've tried zap-a-gap and other types of cynoactlayte (Sp?) and they don't seem to work to my satisfaction. Maybe the setting time is too long or something, but my models always seem to fall apart. Soldering the plastic together works well but it leaves messy seams and isn't good for interior pieces.

What glues does everyone use for their PLA models? A list of brands would be helpful (especially anyone living in NYC).

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[Eric Cheung]

Common super glue would work. Working time is a little short, only a few seconds, but it holds very well!

[Michael Buffington]

Common super glue is cyanoacrylate (same as the Zap-a-Gap Alex mentioned). It's also known as CA glue . I've tried several brands/thicknesses of CA and haven't found any that bond that well. Rubberized CA has the best bond, but as far as bonds go, it's poor. Even after sitting over night I can break the part free. On porous materials, CA, and especially rubberized CA, are usually much stronger than the materials they are bonding (like balsa wood).

Since I don't know the answer I'll do some testing this evening. I have a pretty big collection of glues I can try, most commonly available.

[Wingcommander whpthomas]

I used five minute epoxy on this with spring clamps. But I designed it so every piece has some form of registration. The two sides of the wheel plates were registered to a hub, tires registered to the wheel plates. Front frame registered to the head tube caps, rear frame registered crank bracket caps. All the other parts either screwed or snapped together.

[Alex Lau]

Well, I've found that I can drink out of my cup which is printed at 100% infill..It's not really 'waterproof' though, if you leave it out for hours the water will slowly leak out.

You can try painting it with acetone. The outer layers will 'melt' a bit and maybe that will work.

[Laird Popkin]

Acetone by itself doesn't melt PLA.

But it melts ABS just fine, so I've used ABS "slurry" (i.e. ABS scraps melted in Acetone until it's a liquid) and painted it onto PLA to fill in gaps. The mixture seems to get pulled into the gaps in the PLA via capillary action, then the acetone evaporates, leaving the ABS behind filling the gap. It seems to work pretty well, in that the resulting part is certainly stronger than the PLA alone. Though if the colors don't match, the result can look a little strange (e.g. when I used yellow melted ABS on clear PLA). It's probably watertight as well, though I'm not sure I'd want to drink water out of a cup treated with acetone. :-)

[David Kessner]

Alex,

(Disclaimer:  I haven't actually tried this!)

I would try "painting" it with food-grade silicone sealant that has been thinned out using denatured alcohol.  You'd have to experiment to figure out the proper ratio of silicone to alcohol, but I'd guess that around 75% silicone would be good.  I have used a similar method to seal camping tents/tarps at the seams and it works.  The idea is to thin the silicone enough so that it will wick up into the tight spots, and also not leave big clumps on the surface.

I have been wondering if this method would work for making PLA Jello molds as well.  Print it in PLA, seal it, and then pour in the Jello (or whatever).

[Shawn]

I just finished a project using ABS glue from the plumbing aisle of the
local home hardware store. This may be a reasonable substitute for the
hand made ABS slurry. I have no clue how this would work with PLA, but
Laird's post suggests it might do the trick. With ABS, I'm finding that
it sets up fast and creates a bond stronger that the surrounding
plastic. (at least my 20% fill parts...) I tried LePage epoxy first -
the one that mentions it works with plastic - and found that while it
does work, the bond is not strong (parts can be easily broken apart
after curing), and it takes too long for the epoxy to "set" enough to
hold the parts on it's own. With the ABS glue, I had about 1 minute to
work with the parts, and they would be sufficiently set after 10 to 30
seconds so that I wouldn't have to hold them any longer.

I really should do some work with PLA... :)

[Joseph Chiu]

I overheard one operator at a meetup that he used lacquer to seal his prints to make a usable cup.  A quick googling shows that woodworkers use lacquer to get their wooden creations to be waterproof, and that there are non-toxic choices.  I haven't tried it myself, but that seems like it could work -- just dunk and soak for a while, and perhaps use a vacuum pot.

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[Chris Donnelly]

Hello,

May be a late in replying, but I was looking for a solution and ended up here.

I work in a school and we have all kinds of adhesives... Tried CA glues and acetone.  Then I tried what we call Tensol 12.  We glue a lot of acrylic together with it and thought I'd give it a go.  Nasty stuff, but it works really well.  It is quite syrupy, so having a chemistry department handy, I got a hold of one of the active ingredients, Dichloromethane.  It is very fluid, and I applied it with a pipette. Worth a try if you can get your hands on some anyways.

Chris

[camstuff]

This is by fare the best glue you will ever use!

caglue.com

Cam

[Sarah Davis]

I would have thought pva glue would be the best option, but it does depend what you want to do.

Sarah

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[CreativeDaemon]

Weld-On #16

You can get it for a great price from McMaster-Carr:

http://www.mcmaster.com/#weld-on-adhesives/=p6ujk8

You get 1 1/2 oz, which is ~7-8 times as much as you get in a regular tube of superglue. It also holds much better.

The stuff is NASTY though so be sure to use gloves and have good ventilation.

I believe this stuff melts the PLA together at a molecular level. I have tested it extensively and the glue hold seems to be the strongest part of the piece.

[Michael Rees]

I'm excited about a glue that a friend found and recommended. its plastruct bondene. One benefit is that you apply it and through capillary action it spreads to the edges of the joint and not over (don't understand but its a beautiful thing). I've used super glue for years, disappointingly on pla, and was resolved to 5 minute epoxy, until I found this. Instant 15-20 second bond or 20-30. THey make one thats non toxic for styrene only, should have bought it to try... And it works with ABS... another glue that works fairly well is DAP strong stik, repositionable for minutes, takes 24 hours to dry. not crazy about it though. Also I've tried heating the area to be assembled with a hot air soldering iron. It works, deformation is a down side. Oh yes... plastruct bondene!!